I’ve been putting this project off for some time. I’ve had all the ATF fluid and a new Mag Hytec pan for quite some time but just didn’t find the motivation to do the work until recently. I’ve changed ATF many times before but this was the first time I had planned to do a complete fluid change by flushing all the fluid out of the cooler and torque converter.
Check out the pictures below to see how it went!
When you do your first automatic transmission fluid change, you learn the hard way that it is going to be extremely messy! If you have a project lined up, it’s always a good idea to save cardboard boxes because you’re going to need them to soak up the oil! In this picture you can see the truck on the lift with a good amount of cardboard underneath it. My supervisors are there as well (Father in law, Stan, and my wife, Lesley).
This is the pan that was stock on the transmission. It’s right out in the open and easily accessible. I worked on my brothers Chevy Silverado recently and it wasn’t so nice.
I’ve found that the best way to do this is to remove every other bolt. Once that is done, loosen one corner’s worth of bolts more than the rest. The desired goal of this is to cause one corner of the pan to drop further than the others, which in turn helps encourage the fluid to funnel out of the lower corner. Loosening them all at the same rate can have filthy results.
It’s always helpful to have a large an underneath to capture the slop.
This is the inside of the transmission after the pan was removed. Removing the filter was simple once the two torx bolts were removed.
The new pan and gasket.
The underside of it. Notice the neat little, magnetized drain plug. Awesome.
On the drivers side of the transmission you will find the front band. I adjusted this by backing off of the lock nut, tightening the screw to 72 inch pounds, then backing up the screw one and 3/4 turns. I then tightened the locknut while trying to keep the screw from turning. Not as easy as it looks.
The rear band is located inside the transmission. As before, the bolt has to be tightened to 72 in pounds, but then this one needs to be loosened by 3 turns. I used a sharpie in both cases to mark the socket so that the number of turns was accurate.
After a new filter was placed on the transmission, the new pan went on easily. I was careful to not over tighten the bolts. Note to self: I need to buy some allen wrench sockets.
This is the fluid return line that comes back from the transmission cooler and torque converter. To do a complete flush, you must remove this and allow the fluid to “return” into a bucket somewhere. To begin, we put about 6 quarts of fresh Amsoil ATF into the truck, then I got my wife to sit in the truck and start it.
I then attached a 1/2 inch clear hose to the return line and ran that into a 1 gallon jug. After lifting the truck up a little, I asked Lesley to shift the transmission into neutral to begin the flow of fluid. Once the jug had filled, she put it into park and turned off the truck. We then put 4 quarts of fresh fluid into the truck and repeated the process. We did this twice before seeing bright red fluid coming out of the hose. This was indicative of a complete flush. I reattached the return line to the transmission, topped off the fluid and we were done!
